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The aim of the study was to establish the colonization of Streptococcus mutans and to determine the possibility of intra-familial transmission in a group of Turkish children and their parents. A total of 56 children participated in the study together with their parents (20 fathers and 49 mothers). Saliva samples were collected from the individuals and cultivated on S. mutans selective TYCSB agar. The typical isolates of S. mutans were identified by using classical microbiological methods, as well as molecular typing of S. mutans clones which was performed by using AP PCR with OPA5 primer for the detection of transmission. The vertical transmission of salivary S. mutans was detected among 14 mother-father-child, 35 mother-child (one twins) and 6 father-child combinations. The homologies of strain types were recorded as 24% and 16.6% for mother-child and father-child combinations, respectively. A significant positive correlation (p<0.001) was found between the infected children and their parents with high S. mutans counts.

The impact of different types of extremely low-frequency electromagnetic fields (ELF-EMF) on the growth of Staphylococcus aureus and Escherichia coli O157:H7 was investigated. The cultures of bacteria in broth media were exposed to sinusoidal homogenous ELF-EMF with 2 and 4 mT magnetic intensities. Each intensity for each bacteria was combined with three different frequencies (20, 40 and 50 Hz), and four different exposure times (1, 2, 4 and 6 h). A cell suspension of each experiment was diluted for the appropriate range and inoculated to Mueller-Hinton Agar (MHA) plates after exposure to ELF-EMF. The number of colony forming units (CFU) of both strains was obtained after incubation at 37 °C for 24 h. Data were statistically evaluated by one-way analysis of variance (ANOVA), statistical significance was described at p < 0.05 and data were compared with their non-exposed controls. Magnetic intensity, frequency and exposure time of ELF-EMFs changed the characteristic responses for both microorganisms. Samples exposed to ELF-EMF showed a statistically significant decrease compared to their controls in colony forming capability, especially at long exposure times. An exposure to 4 mT-20 Hz ELF-EMF of 6 h produced maximum inhibition of CFU compared to their controls for both microorganisms (95.2% for S. aureus and 85% for E. coli).

Alkaliphilic actinomycetes isolated from sediment samples of the Izmir Gulf, Turkey were studied for the production of protease activity. Strain MA1-1 was selected as a good alkaline protease producer as measured by the clear zone diameter by the hydrolysis of skim-milk and casein. The alkaline protease production from the marine alkaliphilic actinomycete MA1-1 was studied by using different carbon and nitrogen sources in medium containing glycerol, peptone, KCl, MgSO 4 , K 2 HPO 4 , and trace elements at 30 ºC for 72 h. Among the different carbon and nitrogen sources, fructose, starch, maltose, D(+) glucose, yeast extract, malt extract, beef extract and peptone provided higher production of protease. Starch was also found to be effective for growth and enzyme production with highest specific activity at 699 U mg -1 . Purification was achieved by adsorption on Diaion HP 20 which resulted in a recovery rate of 68% with a specific activity of 7618 U mg -1 protein and 40-fold purification. The optimum pH and temperature of the partially purified protease were determined as pH 9.0 and 50 ºC, but high activity was also observed at pH 8.0-13.0 and 35-50 ºC. The inhibition profile exhibited by phenylmethylsulphonyl fluoride (PMSF) showed that this enzyme belongs to the serine-protease group.

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